The present invention relates to a head suspension assembly used for a magnetic disk device, which includes a slider with at least one thin-film magnetic head element, a resilient suspension for supporting the slider and a head IC chip.
In such magnetic disk device, the thin-film magnetic head element for writing magnetic information into and/or reading magnetic information from a magnetic disk is in general formed on the slider flying in operation above the rotating magnetic disk. The slider is fixed at a top end section of the suspension made of a resilient thin metal plate extended from one end of each movable arm of the magnetic disk device.
Recently, recording frequency in the magnetic disk rapidly increases to satisfy the requirement forever increasing data storage capacities and densities in today""s magnetic disk devices. In order to realize higher frequency recording, proposed is a head suspension assembly structure with a suspension for supporting both a slider and a head IC chip of a driver circuit for the magnetic head element. According to this structure, since the length of lead lines from the driver circuit to the magnetic head element can be shortened, generation of unnecessary noises from the lead lines can be effectively suppressed resulting high frequency recording characteristics to improve.
Such head IC chip will generates large amount of heat due to the writing current flowing through the IC chip during recording operation. Thus, the IC chip is mounted on a surface of the suspension, which will oppose to the magnetic disk surface in operation, in order to obtain cooling effect of airflow produced by the rotation of the magnetic disk.
However, if the IC chip is mounted on the head suspension assembly, the thickness of the assembly increases by the mounting height of the IC chip. Generally, in the magnetic disk device, in order to increase the recording capacity per magnetic disk, both sides of each disk are used for recording. Also, in order to further increase recording capacity, two or more coaxially mounted magnetic disks are used for recording. Therefore, between two adjacent magnetic disks, two head suspension assemblies for writing/reading operations are existed. Thus, it is difficult to make small the whole thickness of the magnetic disk device with the IC chip mounted head suspension assemblies. This becomes serious problem particularly in a thin magnetic disk device mounted in a notebook type personal computer.
Usually, such suspension has a leaf spring structure. Therefore, if a gap between the head suspension assembly and the magnetic-disk surface is made small too much, the carried IC chip may contact with the disk surface due to bending of the spring. Thus, it is impossible to make the gap small. From this reason also, it is more difficult to make small the whole thickness of the magnetic disk device with the IC chip mounted head suspension assemblies.
Furthermore, since the IC chip is protruded from the suspension-surface, when the head suspension assembly moves at high speed in seeking operation, the IC chip will be influenced from the transverse wind causing resonance characteristics of the suspension such as its resonance level and its resonance frequency to change.
It is therefore an object of the present invention to provide a head suspension assembly, whereby its thickness can be kept small even if a head IC chip is mounted thereon.
According to the present invention, a head suspension assembly includes a magnetic head slider with at least one thin-film magnetic head element, a head IC chip with a circuit for the at least one thin-film magnetic head element, and a support member for supporting the magnetic head slider and the head IC chip. The support member has a recess portion for reducing a protruded height of the head IC chip at a position for mounting the head IC chip.
Since the support member that is a suspension has the recess portion at a position for mounting the head IC chip so that the protruded height of the head IC chip is reduced, the mounted height of the head suspension assembly can be made lower. Thus, it is possible to make small the whole thickness of the magnetic disk device with the head IC chip mounted head suspension assemblies. Also, a possibility that the head IC chip directly contacts to the disk surface decreases when an excessive shock is impressed to the magnetic disk drive. Thus, it is possible to solve problems of carrying the head IC chip on the suspension from occurring. Furthermore, since the protruded height of the head IC chip is small or zero, when the head suspension assembly moves at high speed in seeking operation, it will not be influenced from the transverse wind. In addition, by forming the recess portion in the suspension, the mechanical rigidity of the suspension is increased and thus its resonance characteristics are improved.
It is preferred that the assembly further includes a lead conductor member formed on the support member, the head IC chip being mounted on the lead conductor member, and that the lead conductor member has a recess portion for reducing a protruded height of the head IC chip at a position for mounting the head IC chip.
It is also preferred that the support member has a resilient load beam, a resilient flexure supported by the load beam, and a lead conductor member formed on the flexure. The head IC chip is mounted on the lead conductor member.
In this case, preferably the recess portion is formed in the flexure, the lead conductor member and the load beam at a position for mounting the head IC chip, or the recess portion is formed in the flexure and the lead conductor member at a position for mounting the head IC chip and a via hole is formed in the load beam at a position for mounting the head IC chip.
It is preferred that the recess portion has sidewall surfaces that are gradually inclined from a normal surface of the support member. In this case, the recess portion may have rounded junctions between the normal surface of the support member and the sidewall surfaces. Thus, even if the recess portion is formed, disconnection of the lead conductor can be effectively prevented.
It is also preferred that the recess portion has a flat bottom surface for mounting the head IC chip.
The recess portion may be formed so that only a part of the head IC chip is protruded from a normal surface of the support member, or that no part of the head IC chip may be protruded from a normal surface of the support member. In case that only a part of the head IC chip is protruded, cooling effect by airflow can be obtained, but influenced from the transverse wind. Also, the thickness of the assembly is increased and the resistance against excessive shock is reduced. In case that no part of the head IC chip is protruded, the thickness of the assembly is reduced and the resistance against excessive shock is increased but cooling effect by airflow is somewhat reduced.
Further objects and advantages of the present invention will be apparent from the following description of the preferred embodiments of the invention as illustrated in the accompanying drawings.